Although symptoms of various skin wounds caused by traumata, such as thermal burn, racoma, laceration and incised wound, infectious disease in surgery, postoperative wound, decubital ulcer, temperature impairment, chemical impairment, radiation injury, vessel and lymphangiopathy, and others have developed, these skin wounds are accompanied with a strong pain, in many cases.
Medication of a local anesthetic, short term medication of a steroid for external use, oral administration of a nonsteroidal anti-inflammatory drug, etc. are performed as treatment of a pain accompanying skin wound now. However, medication of the local anesthetic or the external steroid often retards wound healing, and there are anxious about side effects, such as gastric ulcer, in oral administration of a nonsteroidal anti-inflammatory drug.
Moreover, generally, since medication to wound region of a non steroidal anti-inflammatory agent retards wound-healing, such medication in the wound region is considered to be contraindication.
As such reason, in regard to alleviation of a pain associated with skin wound, the positive treatment is seldom performed about the pain accompanying skin wound, and the pain is usually put up with until the wound heals.
On the other hand, some therapeutic agents are developed as a wound healing drug. Although many of them have an action which promotes proud flesh proliferation, medication to the wound of the advanced stages in early stages of thermal burn, etc. may worsen its symptoms on the contrary.
Moreover, about what contains iodine among therapeutic agents for wound, the hypersensitivity to iodine is caused or retardation of wound-healing by the cytotoxicity of iodine, etc. is reported.
By the way, acetylsalicylic acid (it may be called hereafter aspirin) is mainly and widely used in the form of oral administration as an analgesic antipyretic for many years, owing to its powerful analgesic, antipyretic and anti-rheumatism activities, and is a medicine with high safety also with few side effects.
In recent years, the research on application to external preparations of acetylsalicylic acid is advanced.
As what indicated a new pharmacological activity as external preparations, moreover, ointments for treatment of neuralgia in Japanese Patent Publication A 3-72426, external preparations for skin injury in Japanese Patent Publication A 9-235232, dermal administration system for treatment of anti-thrombus and for prevention of cancer in Japanese Patent Publication (Toku Hyo Hei) 8-504198, external preparations for treatment of allergodermia in Japanese Patent Publication A 2001-187739, external preparations for antipruritics in WO 01/47525, etc. are mentioned, respectively.
However, there are no external preparations containing acetylsalicylic acid aiming at preventing a pain in the skin wound area, and that it is not indicated at all about the therapeutic effect of external preparations containing acetylsalicylic acid to the skin wound associated with a pain.